scholarly journals Autonomous node in the short wave radio network

2019 ◽  
Vol 29 (3) ◽  
pp. 26-32
Author(s):  
D. A. Kiba ◽  
A. S. Gudim ◽  
N. N. Liubushkina ◽  
S. G. Marushchenko
Keyword(s):  
Short Wave ◽  
Radio Networks ◽  
Network Node ◽  
Radio Network ◽  
Radio Waves ◽  
Monitoring And Control ◽  
Photovoltaic Panel ◽  
Wave Radio ◽  
Study Results ◽  
Autonomous Nodes

The paper covers questions related to the creation of the comprehensive device designed for long-term autonomous operations as part of the radio networks for various purposes in short-wave bands. Such radio networks are intended for remote monitoring and control over facilities at distances of hundreds and thousands of kilometres. The device and features of functioning of autonomous nodes in short-wave radio networks are based on daily and seasonal characteristics of distribution of radio waves, operation under conditions of self-provision with electricity and in areas of harsh climate, as well as on impossibility of their timely repair and maintenance. The authors have proposed solutions to the issue of a reliable communication channel using advanced low-energy types of angle modulation with low-value signal-to-noise ratios and the choice of the best frequency for a given time of the day for specific nodes. There is an overview of issues related to the choice of an antenna type for the autonomous radio network node, taking into account changes of working ranges. The issue of power supply to the radio network node is solved by applying the combination of a photovoltaic panel and wind generator working from a frost-resistant battery. Thermal modes for electronic equipment are provided through the use of a thermostatically controlled container. Authors have presented a possible architecture for the short-wave range radio network node. The study results include advice for developers of autonomous nodes of shortwave radio networks.

Depolarization of short-wave radio waves in the ionosphere in the quasiisotropic approximation

1987 ◽  
Vol 30 (1) ◽  
pp. 29-33 ◽  
Author(s):  
V. G. Tokar' ◽  
L. I. Rubinshtein ◽  
M. A. Nikitin
Keyword(s):  
Short Wave ◽  
Radio Waves ◽  
Wave Radio

scholarly journals Constant-Length Labeling Schemes for Deterministic Radio Broadcast

2021 ◽  
Vol 8 (3) ◽  
pp. 1-17
Author(s):  
Faith Ellen ◽  
Barun Gorain ◽  
Avery Miller ◽  
Andrzej Pelc
Keyword(s):  
Collision Detection ◽  
Background Noise ◽  
A Priori ◽  
Deterministic Algorithm ◽  
Radio Networks ◽  
Positive Answer ◽  
Radio Network ◽  
Constant Length ◽  
Strong Property ◽  
Radio Broadcast

Broadcast is one of the fundamental network communication primitives. One node of a network, called the s ource, has a message that has to be learned by all other nodes. We consider broadcast in radio networks, modeled as simple undirected connected graphs with a distinguished source. Nodes communicate in synchronous rounds. In each round, a node can either transmit a message to all its neighbours, or stay silent and listen. At the receiving end, a node v hears a message from a neighbour w in a given round if v listens in this round and if w is its only neighbour that transmits in this round. If more than one neighbour of a node v transmits in a given round, we say that a c ollision occurs at v . We do not assume collision detection: in case of a collision, node v does not hear anything (except the background noise that it also hears when no neighbour transmits). We are interested in the feasibility of deterministic broadcast in radio networks. If nodes of the network do not have any labels, deterministic broadcast is impossible even in the four-cycle. On the other hand, if all nodes have distinct labels, then broadcast can be carried out, e.g., in a round-robin fashion, and hence O (log n )-bit labels are sufficient for this task in n -node networks. In fact, O (log Δ)-bit labels, where Δ is the maximum degree, are enough to broadcast successfully. Hence, it is natural to ask if very short labels are sufficient for broadcast. Our main result is a positive answer to this question. We show that every radio network can be labeled using 2 bits in such a way that broadcast can be accomplished by some universal deterministic algorithm that does not know the network topology nor any bound on its size. Moreover, at the expense of an extra bit in the labels, we can get the following additional strong property of our algorithm: there exists a common round in which all nodes know that broadcast has been completed. Finally, we show that 3-bit labels are also sufficient to solve both versions of broadcast in the case where it is not known a priori which node is the source.

Atmospheric Effects on Short-Wave Radio Propagation

Nature ◽  
1949 ◽  
Vol 163 (4155) ◽  
pp. 958-959
Author(s):  
J. S. MCPETRIE ◽  
B. J. STARKEY
Keyword(s):  
Short Wave ◽  
Radio Propagation ◽  
Atmospheric Effects ◽  
Wave Radio

scholarly journals Impact of reflective roofs on the overall energy savings of whole buildings

2020 ◽  
Vol 172 ◽  
pp. 25008
Author(s):  
Hamed H. Saber ◽  
Ali E. Hajiah ◽  
Wahid Maref
Keyword(s):  
Energy Savings ◽  
Three Dimensional ◽  
Short Wave ◽  
Solar Absorption ◽  
Thermal Emissivity ◽  
Study Results ◽  
Potential Energy Saving ◽  
Energy Simulations ◽  
Cool Roofs ◽  
Storey Building

Many previous studies by the authors of this paper and others have shown that installing white/reflective/cool roofing systems resulted in energy savings. The amount of energy savings depended on the longwave thermal emissivity and the short-wave solar reflectivity of the rooftop surfaces. The question is “what is the percentage energy savings for the whole building as a result of using cool roofing systems instead of conventional/black roofing systems? To answer this question, three-dimensional energy simulations are conducted for typical Saudi buildings when they are subjected to the natural weathering conditions of the Eastern Province of Saudi Arabia. Several Window-to-Wall Ratios (WWRs) having different thermal resistances (R-values) and Solar Heat Gain Coefficients (SHGCs) are considered in the study. The windows are located in the different main solar orientations. To investigate the effect of the area ratio of the roof to the walls on the potential energy saving due to using cool roofs, one storey and two-storey are considered in this study. Results showed that using reflective materials with lower short-wave solar absorption coefficients in the roofing systems have resulted in a decrease in the yearly total energy loads of one-storey building and two-storey building.

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